原则
编写代码单元应该少于15行，方便阅读、理解、测试、重构，超过15行应提取拆分，直至少于15行。
应用
下面我们通过例子来应用此原则。原代码如下：
func initEngine() *gin.Engine {
router := gin.Default()
m := melody.New()
m.Config.MaxMessageSize = 10024
m.Config.MessageBufferSize = 5120
Rooms = make(map[string]RoomInfo)
router.GET("/v", func(c *gin.Context) {
m.HandleRequest(c.Writer, c.Request)
})
m.HandleConnect(func(session *melody.Session) {
log.Info("[ws] connect:", session)
})
m.HandleDisconnect(func(session *melody.Session) {
log.Info("[ws] disconnect", session)
})
m.HandleMessage(func(session *melody.Session, msg []byte) {
reg, exists := session.Get("reg")
log.Info("[ws] message:", string(msg), "reg:", reg)
if string(msg) == WebSocketClientBye {
if exists {
sp := (reg).(*WSMessage)
if removeRoom(sp.RoomID, sp.ClientID) != "" {
log.Warnf("Socket removeRoom error:%v", reg)
}
}
log.Info("Socket bye", reg)
return
}
message := &WSMessage{}
err := json.Unmarshal(msg, message)
if err != nil {
log.Error("Json error :", err)
return
}
switch message.CMD {
case "register":
log.Debug("register")
session.Set("reg", message)
return
default:
log.Debug("socket default json:", message)
// check
p := (reg).(*WSMessage)
roomID := p.RoomID
my := p.ClientID
m.BroadcastFilter(msg, func(s *melody.Session) bool {
if reg, exists = s.Get("reg"); exists {
sp := (reg).(*WSMessage)
if r, ok := Rooms[roomID]; ok {
for _, c := range r.Clients {
if (sp.ClientID == c.ClientID) && (c.ClientID != my) {
log.Info("[ws] <----sent---->", c, my, string(msg))
return true
}
}
} else {
log.Warnf("[ws] only myself???? roomID:%d,my:%v,msg:%v", roomID, my, string(msg))
}
}
return false
})
}
})
return router
}
这是一个初始化并实现WebSocket与Web功能的服务器，省略部分代码，并删除了一些调试信息。注释少的可怜，如果初次到这样的代码一定会觉得头大。在重构过程中发现使用此原则会让代码结构清晰，这也是我们重构的目的。下面简单介绍使用的方法：
当函数内容太多的时候一定是把所有功能塞到一起了，应该想办法把相同的功能抽离出新的函数。
原代码：
m.BroadcastFilter(msg, func(s *melody.Session) bool {
if reg, exists = s.Get("reg"); exists {
sp := (reg).(*WSMessage)
if r, ok := Rooms[roomID]; ok {
for _, c := range r.Clients {
if (sp.ClientID == c.ClientID) && (c.ClientID != my) {
log.Info("[ws] <----sent---->", c, my, string(msg))
return true
}
}
} else {
log.Warnf("[ws] only myself???? roomID:%d,my:%v,msg:%v", roomID, my, string(msg))
}
}
return false
})
重构代码：
// SendRoomBroadcast 发送房间广播
func (wss *WebSocketServer) SendRoomBroadcast(roomID, my string, msg []byte) {
wss.Server.BroadcastFilter(msg, func(s *melody.Session) bool {
if reg, exists := s.Get("reg"); exists {
sp := (reg).(*WSMessage)
if r, ok := Rooms[roomID]; ok {
for _, c := range r.Clients {
if (sp.ClientID == c.ClientID) && (c.ClientID != my) {
return true
}
}
} else {
log.Warnf("[ws] only myself???? roomID:%d,my:%v,msg:%v", roomID, my, string(msg))
}
}
return false
})
}
当代码整理差不多后，会发现有很多相同的功能，当相同的功能太多的时候可以考虑封装成类。
// WebSocketServer 结构体
type WebSocketServer struct {
Server *melody.Melody // websocket
}
// NewWebSocketServer 初始化WebSocketServer
func NewWebSocketServer(router *gin.Engine) *WebSocketServer {
wss := &WebSocketServer{
Server: melody.New(),
}
// 配置buffer size
wss.Server.Config.MaxMessageSize = 10024
wss.Server.Config.MessageBufferSize = 5120
// 升级为websocket
router.GET("/v", func(c *gin.Context) {
wss.Server.HandleRequest(c.Writer, c.Request)
})
// 处理连接
wss.Server.HandleConnect(wss.handleConnect)
// 处理断开连接
wss.Server.HandleDisconnect(wss.handleDisconnect)
// 处理消息
wss.Server.HandleMessage(wss.handleMessage)
return wss
}
func (wss *WebSocketServer) handleExit(reg interface{}, exists bool, msg []byte) bool {
if string(msg) == WebSocketClientBye {
if exists {
sp := (reg).(*WSMessage)
if removeRoom(sp.RoomID, sp.ClientID) != "" {
log.Warnf("Socket removeRoom error:%v", reg)
}
}
log.Info("Socket bye", reg)
return true
}
return false
}
// SendRoomBroadcast 发送房间广播
func (wss *WebSocketServer) SendRoomBroadcast(roomID, my string, msg []byte) {
wss.Server.BroadcastFilter(msg, func(s *melody.Session) bool {
if reg, exists := s.Get("reg"); exists {
sp := (reg).(*WSMessage)
if r, ok := Rooms[roomID]; ok {
for _, c := range r.Clients {
if (sp.ClientID == c.ClientID) && (c.ClientID != my) {
return true
}
}
} else {
log.Warnf("[ws] only myself???? roomID:%d,my:%v,msg:%v", roomID, my, string(msg))
}
}
return false
})
}
func (wss *WebSocketServer) handleMessage(session *melody.Session, msg []byte) {
reg, exists := session.Get("reg")
log.Info("[ws] message:", string(msg), "reg:", reg)
if wss.handleExit(reg, exists, msg) {
return
}
message := &WSMessage{}
err := json.Unmarshal(msg, message)
if err != nil {
log.Error("Json error :", err)
return
}
switch message.CMD {
case "register":
log.Debug("register")
session.Set("reg", message)
return
default:
log.Debug("socket default json:", message)
wss.SendRoomBroadcast((reg).(*WSMessage).RoomID, (reg).(*WSMessage).ClientID, msg)
}
}
func (wss *WebSocketServer) handleConnect(session *melody.Session) {
log.Info("[ws] connect:", session)
}
func (wss *WebSocketServer) handleDisconnect(session *melody.Session) {
log.Info("[ws] disconnect", session)
}
总结
这个原则足够简单，只要有耐心就能办到。还是建议大家拿起自己手中的代码体验一下，在重构过程中慢慢体会，不过一定要写测试哦，要不就变成裸奔啦。欢迎拍砖：）
